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DIY Junkie
Air quality beginner

FiltAirs DIY Air Filter

A box fan and two furnace filters taped into a triangular air cleaner.

by Open-Source-Imports · CC-BY-SA-4.0

Source: https://www.appropedia.org/535_FiltAirs_DIY_air_filter. Original author: Bikash Pradhan, Nicole Salas, Amin Younes · CC-BY-SA-4.0.

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DIY air unit final product
The finished unit
Estimated cost
—
Tools
2
Time
An hour

Summary

A low-cost air filtration unit built from a box fan, two filters and cardboard, assembled with duct tape.

Build steps

9

  1. Place the fan face down

    Place the unit face down with the inlet side up.

  2. Attach the first filter

    Place one filter on the unit and align it with the edge of the box fan, and verify that the arrow on the filter points towards the fan.

    Filter taped to box fan

  3. Form the triangle

    Sit the unit up and pull both filters out to form a triangle, and secure the point of the triangle.

    Triangle-shape design

  4. Cut the cardboard triangles

    Using the box that the box fan came in, or other cardboard with at least 20x20 inch dimensions, cut out two triangles.

    Cutting out triangles

  5. Cap the top

    Place one triangle on top of the filters, making sure the cardboard slightly overlaps onto the filters.

    Triangle placed on filters

  6. Secure the edges

    Gently fold the edges of cardboard to sit flush against the box fan and secure with duct tape.

    Edge of Triangle Secured

  7. Cap the bottom

    Flip the unit over so the bottom of the fan is facing up, and attach the other triangle to the bottom.

    Cord taped outside

  8. Seal it

    Lay the unit down with the box fan on the ground and the point of the triangle facing up, and seal the remaining edges.

    Securing and sealing edges

  9. Use it

    The unit is assembled and ready to be used. Place the unit sitting upright in an open area.

    DIY air unit final product